The goals of the proposal are to develop a defined medium for the serial cultivation of human sebaceous cells (acinar and ductile), to further characterize the lipids, proteins, and glycoproteins synthesized by the isolated cells, and to determine how androgens and retinoids control lipid production and cell maturation. To determine lipid synthesis, acinar cells will be pulsed with C14-acetate and C14-glucose and polar and non-polar lipids will be separated by sequential thin layer and gas chromatography. Lipogenesis by component cells and by intact glands in organ culture will be compared to verify the accuracy of the cell models. To study fibrous protein synthesis, cells will be labeled with S35-methionine and keratin polypeptides analyzed by polyacrylamide gel electrophoresis. To follow maturation and the factors which control this process, transglutaminase will be asayed in both acinar and ductile cells. The above analytical procedures will be used to determine how androgens (dihydrotestosterone) and retinoids (13-cis retinoic acid) regulate growth, protein, and lipid synthesis in sebaceous cells. We will specifically test the hypothesis that retinoids control growth in acinar cells by altering specific membrane glycoproteins, and that wax ester synthesis occurs only during the terminal maturation of acinar cells. In the past, studies of human sebaceous gland function and metabolism were limited to the collection and analysis of skin surface lipids and to the study of the intact glands in skin biopsies. No methods to isolate and study viable individual cells of the gland have been available. The studies of this proposal will provide a new in vitro model for the study of the normal human sebaceous cell and will establish the basic biochemistry of this cell line. The long range goal of the investigator is to use these cells as models to determine the physiologic and biochemical changes that produce acne.